A variety of wrenches are commonly used to apply torque to a work piece, such as a threaded fastener. The work piece may have any number of different sizes and shapes. Accordingly, many wrenching tools include a driver which is mateable with any of a number of different adapters, such as sockets, to engage and rotate the different-sized work pieces.
Many times these wrenching devices are used to apply torque to fasteners that are in difficult-to-reach spaces or spaces which have limited room in which to adjust and/or turn the fasteners. In such situations, extensions are typically attached between the wrenching devices and sockets to enable the wrenching devices to reach fasteners in difficult locations. These extensions are typically solid, cylindrical extensions which connect to the head of the wrenching device and to the socket. The extensions come in many different sizes to accommodate different extension lengths and different-sized fasteners. These type of extensions are limited in that, when a fastener is tightened or loosened, the distance between the wrenching device and fastener changes as the fastener moves closer to the wrenching device as it is being loosened or away from the wrenching device as it is being tightened. In some situations, the user has to change to a different size extension to accommodate for the change in distance between the fastener and the wrenching device during use.
Other extensions include a tubular outer member and a solid inner member which slides within the outer member to adjust the extension to different incremental lengths without having to completely change the extension. One such extension is described in U.S. Pat. No. 4,376,397 and is directed to an adjustable extension including a driver-engaging member moveable within a work-engaging member. The extension includes a plurality of detents that are spaced along the length of the driver-engaging member and are engaged by a latch member to hold the work-engaging member at one of various different incremental positions. As a result, only one extension is needed. This type of extension, however, requires a user to continuously adjust the incremental position of the extension based on the distance between a wrenching device and a fastener, which takes significant time and effort.
Another type of extension includes an outer member and an inner member that is slidable within the outer member. A spring biases the inner member outwardly away from the outer member to adjust to the changing distances between the wrenching device and the fastener as the fastener is being tightened or loosened. These extensions have limited extension or compression lengths because space is needed for the spring seated inside the extension. Also, the diameters of the outer member and the inside member are very similar in size, which may lead to the extension binding or locking up during use. This type of extension therefore is limited in its extendability and can lead to increased costs and delays due to the extension binding up or breaking during use.
Accordingly, there is a need for an adjustable extension for a wrenching device which automatically adjusts during use and which helps to prevent the extension from binding during use.